Electrified vehicles differ from conventional motor vehicles because electrified vehicles are selectively driven using one or more electric machines powered by a traction battery. The electric machines can drive the electrified vehicles instead of, or in addition to, an internal combustion engine. Example electrified vehicles include hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), fuel cell vehicles (FCVs), and battery electric vehicles (BEVs).
The traction battery can be used to selectively power the electric machines and other electrical loads of the electrified vehicle. The traction battery includes a plurality of interconnected battery cells that store energy for powering these electrical loads. The battery cells are typically housed within an enclosure. Enclosures are typically a metal or metal alloy. Some enclosures are now polymer-based. At certain pressures, such as the pressures exerted by threaded fasteners, polymers can creep.